here is my card, http://www.bfgtech.com/5900_redux.html only difference is that the heatsink cover is chrome on my card (doesn't look chrome in that picture). Its actually a very good cooling solution (pure copper), but unfortunately it still runs hot with its original BIOS modded with increased voltage and lowered latencies. I may have said before that the 5900 bios runs hotter than the 5950 bios, but overall I am getting better performance with the 5900 BIOS. So what I am thinking of doing is modding my side panel and adding 1 or 2 fans to blow directly on the card itself. I have already added extra fans to my HDD, CPU, and chipset to help keep them cool, so a couple more should do the trick.

rewt, Althogh your heatsinking looks fine, I dont think it is good enough for running your card at 5950u levels and beyond ?? I keep saying to people, that a 5950u card has very good heatsinking because it has to remove a lot of heat, and its only running at 475/950 ??

I therefore suggest, you definately fit case side fans to blow more airflow over your card ! But also remember its not only important to get the right airflow accross the internal components, its also just as important to ensure good airflow through the case to keep things cool !

My Aopen 5900nu which is flashed to a MSI5950u and running at 300/500/1000, is based on the original Nvidia design and therefore is fitted with the original large black heatsinks over core and memory chips ! So heat is under reasonable control ! And as I said before, I also have a side fan blowing more air over both my overclocked CPU and overclocked 5900 !!

well, if you take a look at the BFG 5950 it has the same cooling design (with added heatpipe to cool the memory on the rear side). Check http://www.bfgtech.com/5950u_redux.html However, something has been done to the 5950u BIOS to decrease temps, but not quite sure what that is. Any suggestions?

well, if you take a look at the BFG 5950 it has the same cooling design (with added heatpipe to cool the memory on the rear side). Check http://www.bfgtech.com/5950u_redux.html However, something has been done to the 5950u BIOS to decrease temps, but not quite sure what that is. Any suggestions?

I saw that their BFG5950u used the same design, and it is going to run hot ! But not as hot as yours running at the same or higher speeds, as I believe 5950u cores are specially selected and 5950u's memory chips can naturally run at 1000MHz ? Also, there are many parameters within the 5950u bios controlling timings and thus temperatures, however this is an area still being looked at ? From my perspective however it can only be looked at for 5900nu's, but will hopefully ultimately provide the info you seek ?

also, don't be fooled that a 5950u runs cool all the time ??? run the rivatuner realtime hardware monitor, then run your high stress game or performance test, and see just how high the core temp gets ? When playing about with extreme overclocking and high stress testing, I have had my card at 90c+ ! Fortunately with no lasting side effects !

Typical temps for various standard clocked 59xx cards can be seen here,

jimmor,
power supply is thermaltake 480 (550 peak)
using forceware 61.12
As for it being a chaintech, thats what the origional bios says the manufacturer
is, so bfg just slapped fan/hs and memory hs , then upped the core/mem?

I tried the chaintech bios' but it ran slower, probably a heat issue.
The whole problem may be heat related ?
Will be a few weeks before I look for a cooling solution and retry.
Saved all my bios files so just a matter of flashing/testing
Thanks for all the info and help!

jimmor,
power supply is thermaltake 480 (550 peak)
using forceware 61.12
As for it being a chaintech, thats what the origional bios says the manufacturer
is, so bfg just slapped fan/hs and memory hs , then upped the core/mem?

I tried the chaintech bios' but it ran slower, probably a heat issue.
The whole problem may be heat related ?
Will be a few weeks before I look for a cooling solution and retry.
Saved all my bios files so just a matter of flashing/testing
Thanks for all the info and help!

my advice on using another chaintech or Aopen bios was based on peoples experience at Guru forum ? The Aopen was especially popular !

With all the load you have on your PSU, there is very little safety margin ! Also some PSU's don't work that well on all lines ? The 12v line is crucial to your cards performance ?? What is your PSU 12v rating ? and have you made sure you are not sharing your cards connection with any other loads, especially DVD/CD/HDD devices ???

jimmor,
tried the aopen bios too but the memory still is too hot.
I had bought some bfg heatsink kits and used the little ones.
I cut them to fit each single memory.
As bfg didnt put the thermal monitor, and I have no temp monitor
I just physically,carefully, touch the mem sinks and thier hot enough
to burn fingers if constant contact is made, way too hot.
I didnt change gpu core , is at 390/430 memory,even at bfg stock speed
736 will roast my flanges (fingers)
I know I'm running the ragged edge but obtain no problems, weather it be burning a full dvd , running a game , or just surfing the web.

As a test to see how high I could go, I ran at 390/430/930 way o/c'ing
(actually hopeing to burn it up) I already ordered a leadtech, lol

It ran w/o lockups or artifacts!!! but gpu core reset to 399.
Checking temps I first just tried to touch back of the pcb of video card
and it was extremely roasting, needless to say, I didnt get near the memory sinks but gpu core was cool !!!
I've reflashed back to stock, these are well built for taking extreme heat, I'll give bfg/chaintech that credit, although I wouldnt run like that too long,

I am currently using an Albatron 5950 bios flashed on my Albatron 5900 with 2.2 ns memory. It works great, no problems.

I want to do the memory latency mod and change the 43 to 40. Using the hex editor in XBios, I did this with a copy of the bios and saved it. Now all I have to do is reflash my video card just as I did before, right? (Using the modified bios of course, and wfflash which is what I used before).

From reading these threads this seems to be the only mod I want to do to the 5950 bios. Is it ok to just adjust the latency values and nothing else? Or must I adjust another value?

Thanks for your efforts jimmor, cstring and others. Im learning a lot and also gaining valuable performance at the same time

you will definitely want to make sure coolbits isn't overclocking your card at startup. leave it at default (950) for the time being then after flashing you can overclock from there. point is, the lower latencies may not allow you to overclock the mem as high as before, so if you were to flash the bios with lower latencies, and coolbits or some other program is set to overclock say 1000mhz at startup, something bad could happen if ya know what I mean. just be cautious. oh, and i'd prefer use nvflash -5 -6 file.rom to flash the card.

I now have an XFX 5900XT, so I took a look at the BIOS on it (backed it up). Instead of this:
"07 03 0F 03"

I have this:
"07 03 0F 43"

Since ending it with '40' was considered a good timing for overclocking, I suppose I have nothing to do, as mine is already better.

That's probably why I hit 960 memory on stock cooling and voltage.

I guess the question is....would it be worth anything taking this higher? 50, maybe? Or, would the timings start being too loose for the increased overclock potential to make up the difference? (IE, diminishing returns catches up with us, there?)